The invention relates to a shoe sole comprising an outsole consisting of a tough, abrasion-resistant material, a perforated insole, which faces the foot and consists of leather or fabric, and a resilient intermediate layer with ribs extending transversely relative to the longitudinal direction of the sole.
A shoe sole consisting of plastics material or rubber is known from the German Utility Model 84 37 213. This shoe sole comprises a continuous, abrasion-resistant outer layer with a formed on rim. Resiliently deformable webs are molded in the surface facing the foot in the shape of a grid. These webs slope upward toward the front, starting from the outer layer, and end with the upper edge of the sole surface. This sloping arrangement is supposed to circumvent the disadvantage that a relatively hard and abrasion-resistant material must be used for the production of the outsole, while it is better for the feet and the ankles of the shoe wearer if the shocks during walking are cushioned in a resilient and soft manner.
The substantial disadvantage of this known outsole consists in the high costs of production. An individual plastics material injection mold must be produced in each instance for every shoe size, every shoe width and for the right and left feet. Only large firms with great numbers of units and large scales can support such costs. Smaller firms, or firms which only produce shoe models in smaller numbers of units, must look for other, cheaper solutions.
Insert soles are known from US-PS 4 215 492 and US-PS 4 224 746 which can be inserted in conventionally manufactured shoes. Both insert soles comprise an upper side and a lower side of airtight material; perforations are inserted in the upper side so that the soles of the feet of the shoe wearer are aerated by means of the reciprocal rolling motion of the insert sole during walking.
The insert sole of US-PS 4 215 492 comprises additionally raised protuburances on the upper side, which are supposed to massage the front portion of the foot of the shoe wearer.
A massaging sandal is known from US-PS 4 095 253 in which the surface facing the foot is provided with a plurality of pointed protuberances. Such sandals can only be worn for a relatively short time. Since these sandals are injection molded from plastics material, high costs again arise in the production of the required injection molds.
An aerated sole for shoes is known from US-PS 4 364 186. A rigid, perforated insole is fastened on an outsole which opens upward and consists of a resilient material. The hollow space between the outsole and the insole can be reinforced with resilient, springing inserts.
Such an outsole is not usable in practice. First, it is uncomfortable for the foot always to stand on the hard insole. Slight whistling or hissing noises occur because of the pressing out of the air from the intermediate space between the insole and the outsole. However, the worst is that the outsole itself is resilient; the foot of the shoe wearer can therefore bend easily to the right or left, the walk becomes unsure, and a strained ligament is the certain result.